2021-11-28 Pageview:865
Zhanxin additives improve the performance of coating formulations.
Additives enhance the performance of coating formulations by modifying rheological properties, increasing leveling, reducing foam, improving pigment dispersion, accelerating curing and crosslinking, improving adhesion and reducing defects.
Zhanxin’s portfolio includes low VOC and no hazardous air pollutant (HAPS-free) technologies for solvent-borne, waterborne, high solids, powder coatings and energy curing systems in established and emerging markets.
Defoamer
In powder coating formulations, the function of defoamer is to prevent the surface of the coating when powder coating cast iron, cast aluminum, galvanized steel and hot-rolled steel plates with blisters or pinholes on the surface of the coating (workpiece). Additives added to cause defects such as particles (particles) or volcanic craters, that is, additives added to prevent bubbles from forming in the coating film.
When powder coating is applied to cast iron, cast aluminum, galvanized steel and hot-rolled steel sheets with blisters or pinholes, during the baking and curing process, the powder coating melts and flattens and seals the surface of the coated object. Trachoma and pinhole. As the temperature of the coated object increases, the air in the blisters and pinholes of the coated object expands, and the internal pressure also continues to increase. When the internal pressure is slightly greater than the strength of the olefin fusion coating film, the internal air will blow the coating film. Become small bubbles and escape. Because the powder coating undergoes a chemical reaction during the film formation process, the melt viscosity of the coating is constantly increasing, and it becomes a solid coating film. Therefore, when the internal pressure in the small bubbles does not reach the energy to burst the coating film, these small bubbles are formed The particles or particles (some called sand particles) protruding from the surface of the coating film; when the internal pressure in the small bubbles is enough to blow up the energy of the coating film, the small bubbles will burst, and the air inside will escape to the atmosphere. If the coating film at this time has lost its leveling properties and cannot bridge the small pores through which the air escapes, the formation of typical particles or particles with small volcanic craters will become a serious problem of the coating film.
If the defoamer is added to the powder coating formulation, the defoamer can reduce the melt viscosity of the powder coating and at the same time reduce the surface tension of the powder coating, so that the blisters and pinholes on the surface of the coating will increase in pressure due to the baking temperature. The uncured air, which has a large capacity to bulge and level the uncured coating film, run into the atmosphere. At the same time, the pores of the debubbled coating film can also easily bridge the leveling, so that the coating film can avoid particles or particles, or produce small volcanic craters. Particles or particles.
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